Soy protein isolate-konjac glucomannan hydrogel as a sodium reservoir for flavor modulation and texture enhancement in low-salt Antarctic krill surimi

Antarctic krill ( Euphausia superba ) surimi faces commercialization challenges due to endogenous proteases causing poor gelation, exacerbated by sodium reduction strategies aimed at mitigating health risks from high salt consumption. This study innovatively utilized soy protein isolate-konjac glucomannan (SPI-KGM) sodium-loaded hydrogel as a functional sodium carrier to enhance the quality of low-salt (1.5 % NaCl) Antarctic krill surimi. The hydrogel's structural stability, sodium-loading capacity (1.47 g/100 g at 3 % KGM, pH 7), and heterogeneous sodium distribution were systematically characterized via confocal laser scanning microscopy (CLSM), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). Incorporation of 20 % hydrogel into low-salt surimi significantly improved water-holding capacity (WHC) by 54.07 % and gel strength by 2.35-fold compared to the low-salt control, while reducing cooking loss by 63.16 %. Cryo-SEM revealed a denser, more homogeneous gel microstructure. The hydrogel facilitated targeted sodium release during simulated oral mastication, enhancing saltiness perception by optimizing spatial sodium distribution within the gel matrix, as validated via electronic tongue and in vitro digestion studies. Rheological analysis confirmed enhanced viscoelasticity and structural recovery in hydrogel-modified surimi. These findings demonstrate that SPI-KGM hydrogel simultaneously mitigates texture deterioration and amplifies saltiness perception in low-salt surimi through microstructure engineering and controlled sodium delivery. This strategy offers a dual-functional solution for developing nutritious, sensorially acceptable reduced‑sodium surimi products.